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authorstable-bot for Steven Rostedt <srostedt@redhat.com>2011-02-10 10:21:08 +0100
committerAK <andi@firstfloor.org>2011-03-31 11:57:58 -0700
commit54b79ba6355064fdbcea6bf96e28c148efc1c924 (patch)
tree059bb347281cc3294989bb344f8b7cc176ba467e /kernel
parent758df963bb23a00cb6f2fbf9714ea37d3fa116a8 (diff)
sched: Give CPU bound RT tasks preference
From:: Steven Rostedt <srostedt@redhat.com> Commit: b3bc211cfe7d5fe94b310480d78e00bea96fbf2a upstream If a high priority task is waking up on a CPU that is running a lower priority task that is bound to a CPU, see if we can move the high RT task to another CPU first. Note, if all other CPUs are running higher priority tasks than the CPU bounded current task, then it will be preempted regardless. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Gregory Haskins <ghaskins@novell.com> LKML-Reference: <20100921024138.888922071@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched_rt.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 86a2f77977c..25bd3a3ca0c 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -971,7 +971,8 @@ select_task_rq_rt(struct rq *rq, struct task_struct *p, int sd_flag, int flags)
* For equal prio tasks, we just let the scheduler sort it out.
*/
if (unlikely(rt_task(rq->curr)) &&
- rq->curr->prio < p->prio &&
+ (rq->curr->rt.nr_cpus_allowed < 2 ||
+ rq->curr->prio < p->prio) &&
(p->rt.nr_cpus_allowed > 1)) {
int cpu = find_lowest_rq(p);
@@ -1491,9 +1492,10 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p)
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
has_pushable_tasks(rq) &&
+ p->rt.nr_cpus_allowed > 1 &&
rt_task(rq->curr) &&
- rq->curr->prio < p->prio &&
- p->rt.nr_cpus_allowed > 1)
+ (rq->curr->rt.nr_cpus_allowed < 2 ||
+ rq->curr->prio < p->prio))
push_rt_tasks(rq);
}